In amyotrophic lateral sclerosis (ALS) and other diseases affecting the lower motor neurons, including peripheral neuropathies and some spinocerebellar degenerations, we are seeking (a) more precise morphologic and chemical definition of the abnormalities; (b) separation of each disorder into more distinct, and often new, subforms; (c) specific or symptomatic therapeutic response; (d) new methods of analysing the abnormalities; and (e) animal models of the human pathophysiologic states.